Wideband wireless access systems are 3.5-generation mobile communication systems that use a wireless transmission technique ensuring the usage efficiency of spectrum in a 2.3 GHz frequency bandwidth to provide image and high-speed pack data services, such as various IP-based wireless data services (for example, streaming video, FTP, mail, and chatting) available through the wire Internet. The wideband wireless access system includes access terminals (ATs), base stations (BSs) for supporting the wireless connection and network connection of the access terminals, and a packet access router (PAT) for controlling the mobility of the base stations and performing a packet routing function.
Meanwhile, as the related art, an invention entitled A Band Adaptive Modulation and Coding Managing Method in a Wideband Wireless Access System is disclosed in Korean Unexamined Patent Application Publication No. 2006-60221 (date of publication: Jun. 5, 2006).
Specifically, in the related art, a mobile station can change an allocated subchannel while being operated in the band AMC mode, and thus a subscriber having mobility can be periodically operated in the band AMC mode. In addition, in an IEEE 802.16 WirelessMAN-based wideband wireless access system, it is possible to improve the efficiency of the operation of the band AMC mode.
Meanwhile, as related art, an invention entitled A Packet Scheduling Method in a Mobile Communication System is disclosed in Korean Unexamined Patent Application Publication No. 2005-92145 (date of publication: Sep. 21, 2005).
The related art relates to a delayed proportional fairness scheduling algorithm that is effective in improving the performance of a terminal moving at a low speed or at rest. In addition, in the related art, a method of allocating users with channel values and a method of checking whether channels increase or decrease and forcibly lowering priority when the channels increase has been disclosed.
Specifically, in the related art, general proportional fairness scheduling is not selected in the maximum capacity in a low-speed environment, but is selected when the moving speed is being increased, which prevents a terminal of another user from being selected in a band having a good channel quality due to fairness. That is, in the related art, scheduling is delayed such that the capacity of the users is close to the maximum value. At that time, the user is selected, and a resource is allocated thereto.
Meanwhile, in a data service of the wireless access system, since data transmission speed is an important factor, a method of increasing data transmission speed should be proposed. This is a method of overcoming the limit of resources in the wireless communication technique.
In order to increase the data transmission speed, a band AMC method of discriminating good channels from bad channels considering the state of each subchannel and allocating the subchannel to each terminal in the allowable range of resources has been used in the portable Internet.
When the band AMC method is used, the terminals allocated with resources composed of good channels are modulated to have higher capacity, which makes it possible to transmit data at a high speed.
In the band AMC method, a user terminal measures channel quality information (CQI), collects information on subchannels being operated, and uses a band composed of only the subchannels having a good channel quality on the basis of the channel information. Therefore, the user terminal is little affected by peripheral noise and interference, which makes it possible to improve the coding rate of the terminal to which the band AMC method is applied and for the terminal to transmit data at a high speed.
However, when a band has already been allocated to one mobile station among a plurality of mobile stations having received resources in the band AMC mode and then performed services, it is difficult to allocate the band to other mobile stations. When this process is periodically performed, an unfair service may be provided to the user. Therefore, a service provider may provide an unfair service to the user, or the user may receive an unfair service from the service provider.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.